Tolypocladium inflatum is an asexual ascomycete fungus originally isolated from a Norwegiansoil sample that, in certain conditions, produces ciclosporin.

The fungus from which ciclosporin was first isolated was originally misidentified as Trichoderma polysporum.[1] Gams later showed the fungus belonged in a new genus of molds, Tolypocladium, and he coined the name Tolypocladium inflatum for the ciclosporin fungus.[2] In 1983, Bissett found T. inflatum was the same as Pachybasium niveum, and since the older name would have priority under the rules of botanical nomenclature, Bissett made the combination Tolypocladium niveum.[3] However, because of the economic importance of the fungus in the pharmaceutical industry, the name T. inflatum was later formally conserved to avoid confusion, so today the correct name of the mold that produces ciclosporin is Tolypocladium inflatum.

In 1996, Kathie Hodge and colleagues determined the mold T. inflatum is the asexual state of Elaphocordyceps subsessilis (formerly Cordyceps subsessilis).[4] Whereas the sexual Elaphocordyceps subsessilis state is a pathogen of beetles, the asexual T. inflatum state is widely distributed in soils.